Any Good Vibrations with Bogie Tracks?

Forestry machines are often travelling on unprepared terrain, which means often rather bumpy ride.4-wheeled machines became 6-wheeled and later on 8 wheeled machines to alleviate the worst obstacles. Nordic forestry people discovered if these wheels were arranged in bogie construction the machine (usually a forwarder that could carry timber) both could better negotiate obstacles and with all wheels driven one could get better climbing ability. Still machines could get stuck uphill in a snowy terrain. One way to improve traction was to put steel tracks on the wheels and there we are today. One of the bigger producers of bogie tracks in the world is Olofsfors in Northern Sweden. These tracks are of special steel to last when driving on stones and sand. Steel tracks on stony terrain must mean a bumpy ride for the operator many people are thinking. That is why we decided to test that opinion and Rehn ́s dissertation (2004, R.M.S. values that allowed driving 2.5-3.1 h/day according to the ISO 2631-1 standard) showed that compared to snowmobiles and snow groomers, forwarder drivers belonged to those with most musculoskeletal disorders due to whole-body vibration exposure. In his study the forestry machines had no bogie tracks.